1. Field of the Invention:
This invention like those of my aforesaid copending applications relates to the production of high solids content aqueous latices with reduced losses, from solvent dispersions or cements of polymer compositions, and aims generally to provide improved method and apparatus combination therefor, and new products produced thereby.
2. Description of the Prior Art:
To date, in the practical art, synthetic latices of high polymers have been primarily prepared by emulsion polymerization, which can produce latices of uniform colloidal particle size. In contrast, it is difficult to prepare latices from the class of high polymers made by essentially anhydrous catalyst polymerizations. In this latter case it has been proposed to prepare aqueous latices of high polymers from solvent solutions thereof by processes of the type which comprise the general steps of (1) providing a dispersion or cement of the polymer in a volatile organic solvent for the polymer, (2) adding to such dispersion water and an aqueous emulsifier therefor and emulsifying the same to produce an emulsion, (3) stripping the volatile organic solvent from the said emulsion, and (4) recovering the resulting latex product. However, in the practical art difficulty has been experienced in attempting to render such proposed processes commercially feasible, inter alia, in that (1) aqueous emulsification and stripping of solvent dispersions or cements of the high polymer materials, especailly when dilute, have yielded latices of only medium solids and high emulsifier content which render them commercially impractical; (2) in that the emulsions have tended to foam excessively during stripping; and (3) in that the emulsions have tended to form coagulum by coalescence of the polymer phase as well as by drying out especially on contact with heated surfaces, during the stripping and or concentrating processes, and (4) in that such processes have tended to yield latices of poor mechanical stability, i.e. latices which when subjected to mechanical shear during blending with other materials in the industrial applications thereof, are apt to undergo coagulation thereby rendering the blended materials unsuitable for their intended latex applications especially when the emulsifiercontent is low.